The present invention relates in general to emergency response vehicles, and, more particularly to an emergency response vehicle having a forwardly mounted warning unit.
Various types of ambulances and similar emergency vehicles are fabricated from incomplete vehicle chassis which are provided by automobile manufacturers. The incomplete chassis generally comprises the frame, engine and drive components, and at least a portion of the external body. The chassis is then completed by the addition of various components such as a module containing the desired patient support items. Among the many features added to the basic chassis by the ambulance fabricators are forward warning lights and sirens that are used to signal the presence of the ambulance to drivers in other vehicles. One type of warning unit that has gained widespread acceptance is one that combines a flashing light and siren into a compact device that can be mounted within the grill area of the vehicle. An example of a warning unit suitable for mounting within the grill is disclosed in U.S. Pat. No. 4,884,523 to Wheeler.
Mounting of a warning unit within the grill is desirable because the flashing lights and siren are located at the appropriate level for projection through the rear window of vehicles in front of the ambulance. This placement allows the noise signal to easily penetrate those vehicles and the flashing lights can be readily seen by drivers looking into their rear view mirrors. It has also been determined that this positioning of the warning unit allows the noise signal produced by the siren to be projected farther in front of the ambulance than when the siren is located on top of the ambulance. Because of these advantages, grill mounting of the warning units is now widely accepted both by manufacturers and by the general public which has become accustomed to identifying emergency vehicles by the location of the flashing lights and siren within the ambulance grill.
For many years the basic vehicle chassis supplied by one manufacturer remained substantially unchanged and ambulance builders became accustomed to mounting the forward warning units within the grill of ambulances fabricated from that chassis type. Recently, however, that chassis design has been extensively modified by the vehicle manufacturer. As a result of those modifications, a smaller grill area is now provided and presents a significant problem in the placement of the forward warning units within the grill area. In order to maintain the proper air flow through the radiator and engine compartment required to prevent overheating of the engine, the manufacturer initially directed that no air flow restricting accessories such as flashing lights and sirens be mounted in the grill. Placement of the warning units at other locations on the front end of the vehicle was considered generally undesirable by ambulance builders or was prohibited by the chassis manufacturer. For example, a siren mounted on the top, hood or fenders of the vehicle would produce a significant amount of noise within the ambulance which might exceed that permitted by governmental regulations, a hood or fender mounted unit might interfere with the line of sight of the ambulance driver, and a unit positioned on the hood would be subjected to jarring and possible damage each time the hood is closed. Mounting of the warning units on the front bumper is also discouraged by the manufacturer because of possible interference with the controlled crushing of the vehicle front end during a frontal collision.
In view of the perceived lack of alternative mounting locations for vehicle warning units, ambulance builders have reportedly obtained approval from the chassis manufacturer for the grill mounting of certain warning units that provide only limited air flow blockage. Despite this concession, a need still exists for a vehicle having a readily visible forward warning unit which does not block any of the air flow to the radiator and does not subject the ambulance occupants to objectionable noise levels.